
Whenever this creature attacks, reveal the top card of your library and put it into your hand. You lose life equal to that card's mana valuemana valueThe total amount of mana in a card's cost, ignoring colour. A card costing has mana value 4. X counts as 0 except on the stack. if this creature isn't saddled. Otherwise, each opponent loses that much life.
SaddleSaddleTap any number of other creatures you control with total power 3 or more: This Mount becomes saddled until end of turn. Saddle only as a sorcery. 3 (Tap any number of other creatures you control with total power 3 or more: This Mount becomes saddled until end of turn. Saddle only as a sorcery.)
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Read from the rules text. A card that enables a keyword makes or is the thing; a card that rewards it gets better when you have it. Two cards interact when one enables what the other rewards.